PostgreSQL Query Catalog

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Filter Queries

Found 4 queries.

  • All the queries about database objects contain a subcondition to exclude from the result information about the system catalog.
  • Although the statements use SQL constructs (common table expressions; NOT in subqueries) that could cause performance problems in case of large datasets it shouldn't be a problem in case of relatively small amount of data, which is in the system catalog of a database.
  • Statistics about the catalog content and project home in GitHub that has additional information.

# Name ▲ Goal Type Data source Last update License
1 Avoid using length function This query identifies all expressions that use the non-standard length() function. Although length() is a functional synonym for char_length() in PostgreSQL, its use is discouraged for two primary reasons: char_length() is the SQL-standard function, and length() has different semantics in other database systems (e.g., returning byte length in MySQL). To enhance code portability and prevent semantic ambiguity for developers, this query flags all instances of length() to encourage standardization on the char_length() function. Problem detection INFORMATION_SCHEMA+system catalog base tables 2025-11-13 12:53 MIT License View
2 Inconsistent use of length and char_length functions This query identifies inconsistent usage of string length functions within the database. Although length() and char_length() are functional synonyms in PostgreSQL (both returning the character count), mixing them violates clean coding principles. The query checks if both variants are present in the codebase, flagging a lack of standardization. Enforcing a single choice (typically the SQL-standard char_length or character_length) improves code maintainability and readability. Problem detection INFORMATION_SCHEMA+system catalog base tables 2025-11-13 12:56 MIT License View
3 Routines that use old syntax for limiting rows This query identifies PL/pgSQL and SQL routines with no SQL-standard bodies that use the non-standard LIMIT clause for row limitation. It flags these routines because the official, cross-platform SQL standard specifies FETCH FIRST n ROWS ONLY for this purpose. Adhering to the standard improves code portability and maintainability. To ensure relevance, the query intelligently excludes routines that are part of installed extensions, focusing only on user-defined code. Problem detection INFORMATION_SCHEMA+system catalog base tables 2025-11-21 17:37 MIT License View
4 Usage of the non-standard now() function This query identifies all expressions that use the non-standard now() function. In PostgreSQL, now() is a historical, non-standard alias for the SQL-standard current_timestamp. While they are functionally identical within PostgreSQL (both returning the transaction start timestamp as a TIMESTAMPTZ), the use of current_timestamp is strongly preferred for reasons of code portability and adherence to standards. Standardizing on current_timestamp ensures the code is universally understood and easier to maintain or migrate to other database systems. Problem detection INFORMATION_SCHEMA+system catalog base tables 2025-11-15 10:01 MIT License View